Secreting and Sensing: Epigenetics and the inner voice (2)

Secreting and Sensing the Same Molecule Allows Cells to Achieve Versatile Social Behaviors

Excerpt: By integrating simple mathematical models, measurements on single cells and whole populations, and a bottom-up synthetic biology approach, we revealed a diverse repertoire of biological functions that secrete-and-sense cells can achieve. Crucially, this integrated approach uncovered design principles that enable the circuit to tune the balance between self-communication and neighbor communication among cells—a crucial mechanism for achieving myriad cellular behaviors and an important general issue in biology.

Feedback loops link odor and pheromone signaling with reproduction “”Indications that GnRH peptide plays an important role in the control of sexual behaviors suggest that pheromone effects on these behaviors might also involve GnRH neurons.” p 683.

Signaling Crosstalk: Integrating Nutrient Availability and Sex links the yeast model from the bottom-up natural selection of nutrients to the top-down pheromone-controlled physiology of reproduction. ” The conserved molecular epigenetics of the  “…mechanism by which one signaling pathway regulates a second provides insight into how cells integrate multiple stimuli to produce a coordinated response.” The conserved molecular epigenetics were detailed in From Fertilization to Adult Sexual Behavior  and extended across species in Nutrient-dependent/pheromone-controlled adaptive evolution: a model after other published works fully developed the model that was first presented in 1992.

My comment submitted to Science Magazine submitted on Fri, 02/07/2014 – 16:44 and published on Mon, 2/10/14 at 16:52:

Re: “Evolution appears to favor efficient circuits and signaling elements that can accomplish many different tasks…”

That was inferred in our 1996 Hormones and Behavior review: From Fertilization to Adult Sexual Behavior. We started with the conserved molecular epigenetics of yeasts and extended nutrient-dependent genetic
diversity from the metabolism of nutrients to the pheromone-controlled physiology of reproduction in species from microbes to man.

Four years later our yeast-to-mammalian model was extended by others to hormone-organized and hormone-activated invertebrate behavior, and 5 years after that to the life history transitions of the honeybee model organism.

Since then, “Signaling Crosstalk: Integrating Nutrient Availability and Sex” has linked yeasts to “Feedback loops link odor and pheromone signaling with reproduction” in other species and to “Nutrient-dependent/pheromone-controlled adaptive evolution: a model”

Placing all these published works into the context of evolution as Youk and Lim have done seems somewhat problematic for some evolutionary theorists. The conserved molecular mechanisms appear to represent adaptations to ecological variation via nutrient-dependent secretion of pheromones and the sensing of pheromones.

That links the epigenetic landscape to the physical landscape of DNA in the organized genomes of species from microbes to man.

The fact that ecological adaptations occur via a nutrient-dependent signaling pathway, which regulates a pheromone-controlled signalling pathway shows how unicellular and multicellular organisms produce a coordinated
response to multiple stimuli with no consideration for mutations or for natural selection of anything except food.

That does not present a problem in the context of biologically-based food odor- and social odor-driven cause and effect, but it makes mutation-driven evolution appear to be not only biologically implausible but also to not be
an ecologically valid approach to species diversity.

Author: James Kohl

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